Jacques Alexandre César Charles (November 12, 1746 – April 7, 1823) was a French inventor, scientist, mathematician, and balloonist.Charles wrote almost nothing about mathematics, and most of what has been credited to him was due to mistaking him with another Jacques Charles, also a member of the Paris Academy of Sciences, entering on May 12, 1785. He was sometimes called Charles the Geometer. (See J. B. Gough, Charles the Obscure, Isis 70, #254, pgs 576–579) Charles and the Robert brothers launched the world's first unmanned hydrogen-filled gas balloon in August 1783; then in December 1783, Charles and his co-pilot Nicolas-Louis Robert ascended to a height of about 1,800 feet (550 m) in a manned gas balloon. Their pioneering use of hydrogen for lift led to this type of balloon being named